|
... For more information, call (206) 447-0800.
1.5 NET ORIGINS
In the 1960s, researchers began experimenting with linking computers
to each other and to people through telephone hook-ups, using funds from
the U.S Defense Department's Advanced Research Projects Agency (ARPA).
ARPA wanted to see if computers in different locations could be mail list
linked using a new technology known as packet switching. This technology,
in which data meant for another location is broken up into little pieces,
each with its own "forwarding address" had the promise of letting several
users share just one communications line. Just as important, from ARPA's
viewpoint, was that this allowed for mail address creation of networks that could
automatically route data around downed circuits or computers.
ARPA's
goal was not the mailing list servers creation of today's international computer-using
community, but development of a data network that could survive a nuclear
attack.
Previous computer networking efforts had required a line between
each computer on the network, sort of like a one-track train route. The
packet system allowed for creation of a data highway, in which large
numbers of vehicles mailing list servers could essentially share the same lane. Each packet
was given the computer equivalent of a map and a time stamp, so that it
could be sent to the right destination, where it would then be
reassembled into a message the computer or a human could use.
This system allowed computers to share data and the researchers to
exchange electronic mail, or e-mail. In itself, mail list e-mail was something
of a revolution, offering the ability to send detailed letters at the
speed of a phone call.
As this system, known as ARPANet, grew, some enterprising college
students (and one in high school) developed a way to use it to conduct
online conferences.
These started as science-oriented discussions, but
they soon branched out into virtually every other field, as people
recognized the power of being able to "talk" to hundreds, or even
thousands, of people around the country.
In the 1970s, ARPA helped support the development of rules, or
protocols, for transferring data between different types of computer
networks. These "internet" (from "internetworking") protocols made it
possible to develop the worldwide Net we have today that links all sorts
of mail list computers across national boundaries. By the close of the 1970s, mail list links
developed between ARPANet and counterparts in other countries. The world
was now tied together in a computer web.
In the 1980s, this network of networks, which became known
collectively as the Internet, expanded at a phenomenal rate. Hundreds,
then thousands, of colleges, research companies and government agencies
began to connect their computers to this worldwide Net. Some
enterprising hobbyists and companies unwilling to pay the high costs of
Internet access (or unable to meet stringent government regulations for
access) learned how to link their own systems to the Internet, even if
"only" for e-mail and conferences. Some of these systems began
offering access to the public. Now anybody with a computer and modem --
and persistence -- could tap into the world.
In the 1990s, the Net continues to grow at exponential rates. Some
estimates are that the volume of messages mail list transferred through the Net
grows 20 percent a month. In response, government and other users have
tried in recent years to expand the Net itself. Once, the main Net
"backbone" in the U.S. moved data at 56,000 bits per second. That proved
too slow for the ever increasing amounts of data being sent over it, and
in recent years the maximum speed was increased to 1.5 million and then
45 million bits per second.
Even before the Net was able to reach that
latter speed, however, Net experts were already figuring out ways to pump
data at speeds of up to 2 billion bits per second -- fast enough to send
the entire Encyclopedia Britannica across the country in just one or two
seconds. Another major change has been the development of commercial
services that provide internetworking services at speeds comparable to
those of the government system. In fact, by mid-1994, the U.S.
government will remove itself from any day-to-day control over the
workings of the Net, as regional and national providers continue to
expand.
1.6 HOW IT WORKS
The worldwide Net is actually a complex web of smaller regional
networks. To understand it, picture a modern road network of trans-
continental superhighways connecting large cities. From these large cities
come mail list smaller freeways and parkways to link together small towns, whose
residents travel on slower, narrow residential ways.
mail address The Net superhighway is the high-speed Internet. Connected to
this are computers that use a particular system of transferring data
at high speeds. In the U.S., the major Internet "backbone"
theoretically can move data at rates of 45 million bits per second
(compare this to the average home modem, which has a top speed of roughly
9,600 to 14,400 bits per second).
Connected to the backbone computers are smaller networks serving
particular geographic regions, which generally move data at speeds
around 1.5 million mail address bits per second.
Feeding off these in turn are even smaller networks or individual
computers.
Unlike with commercial networks such as CompuServe or Prodigy, there
is no one central computer or computers running the Internet -- its
resources are to be found among thousands of individual computers.
This mail list
is both its greatest strength and its greatest weakness. The approach
means it is virtually impossible for the entire Net to crash at once --
even if one computer shuts down, the rest of the network stays up. The
design also reduces the costs for an individual or organization to get
onto the network.
But thousands of connected computers can also make it
difficult to navigate the Net and find what you want -- especially as
different computers may have different commands for plumbing their
resources. It is only recently that Net users have begun to develop the
sorts of navigationa ... |
